Biomimetic dandelion-like magnetic nanoparticles for capture and detection of S. aureus and L. monocytogenes

Foodborne pathogenic microorganism pose a serious threat to public health security; thus, constructing quick and sensitive methods for early screening foodborne pathogenic microorganism is necessary for human health. Teicoplanin (Teic) is a broad-spectrum biometric molecule, which can recognize Gram-positive (G + ) bacteria. In this study, using bovine serum albumin (BSA) and PEG 2k as “carrier” and “linker”, respectively. Teic was wired to magnetic beads (MBs) to form the biomimetic dandelion-like magnetic nanoparticles (MBs-PEG-BSA-Teic) to capture Staphylococcus aureus ( S. aureus ) and Listeria monocytogenes ( L. monocytogenes ). The MBs-PEG-BSA-Teic displayed excellent capture ability of S. aureus (> 93%) and L. monocytogenes (> 86%). After separation, the fluorescence probes were added, forming a “sandwich” structural compounds, namely, MBs-PEG-BSA-Teic~bacteria~fluorescence probes. The fluorescence intensity of the probes was measured by a multimode microplate reader. Consequently, this novel method showed high detection sensitivity to target model bacteria, and the detection limit of S. aureus and L. monocytogenes in PBS buffer solution and juice were achieved 10 1 CFU/mL, spinach and ground beef samples were achieved 10 2 CFU/g. The method has easy operation and high sensitivity, and it is less interfered by food matrix or negative bacteria; thus, this method is suitable for early screening G + pathogen in suspected food samples. • BSA and PEG were used to mediate Teic with MBs, introducing multiple binding sites. • MBs-PEG-BSA-Teic with fluorescence method has low LOD and high specificity. • The method can be used for simultaneous detection of multiple G + bacteria.